A Lousy, Nit-Picking Epidemic

Covers the plague of head lice that has descended on United States schools. The difficulty of ridding Pediculus humanus capitis, the human head louse, from hair; The numbers of children affected; The powerful shampoos that no longer work; The evolutions of the lice; The history of the head louse.

A hair-raising plague of head lice has descended on America’s schoolkids. What can stop it?

The school had been invaded, and officials were banning brushes and putting coats in plastic bags to seal off the points of attack. Five nurses worked all morning on the heads of 600 children at the Rachel Carson Elementary School in Gaithersburg, Md., spending five to seven minutes per scalp, looking for signs of infestation. In the end, 12% of the students and 10% of the staff were sent home. It was the worst invasion of head lice in a long time. “In other years we have two, sometimes four cases of lice,” says Laura Hart Silkwood, the principal. “This is highly, highly unusual. The numbers kept rising.”

And not just in Gaithersburg. Pediculus humanus capitis, the human head louse, is back in alarming numbers in school systems from New York to California. The epidemic had nearly been stemmed decades ago by a generation of chemical shampoos and rinses, but now the insect appears to be backed by a force more powerful than any shampoo: evolution.

Thousands of parents and school officials are calling county health offices to report that the standard arsenal of commercial lice-killing products seems to be having little effect. In Iowa, Virginia and Oklahoma, newspaper articles have discussed the merits of such home remedies as olive oil and vinegar. In Rhode Island, Idaho and Florida, parents are trading tips on smearing their kids’ hair with vaseline, steam cleaning the carpets and storing teddy bears in the refrigerator. “It’s creating a lot of havoc,” says Wayne Kramer, the Nebraska state medical entomologist, who has received 125 calls since the beginning of the school year, many more than usual. “I think it’s on the brink of being out of control.”

The human head louse has been around for millenniums. Archaeologists have found evidence of head lice in the hair of ancient Egyptian mummies. And each year, 10 million to 12 million Americans receive unsolicited calls from the sesame seed-size insects, which set up shop in human scalps and lay eggs, or nits, that they cement to hair shafts. Head lice do not carry disease, but they are tenacious and a rather nasty sight. In the past few decades, the problem had been controlled with shampoos or soaps, many of them containing permethrin, the most widely used of the lice-killing chemicals called synthetic pyrethroids. In recent years, however, the frequency of infestations has increased, and ever greater numbers of children are becoming reinfested within days of treatment. All this has led health officials and researchers to begin worrying about the emergence of a resistant strain of the insect, impervious to permethrin.

Researchers speculate that overexposure to permethrin may have sparked a process of natural selection in lice. A similar use of preventive insecticides encouraged the rise of resistant strains of the mosquitoes and black flies responsible for transmitting malaria and African river blindness. Although no definitive studies on resistant strains of head lice have been completed in the U.S. (results of a Harvard investigation won’t be ready for several months), two recent papers from Israel and the Czech Republic seem to support the resistant-strain theory. Says Thomas Bell, health officer for three counties in Washington State: “How do you induce resistance among a population of insects, bacteria or whatever? You expose the population to a sublethal dose of the chemical you’re trying to kill them with, and that way you select for the strongest.”

PHOTO (COLOR): HEADING YOUR WAY Pediculus humanus capitis on strands of human hair, above; the louse may be easy to spot, but the key to ending the scourge is combing out its tiny eggs, called nits

Even though the theory remains to be proved, its implications dovetail with the experiences of parents like Michele Colburn, a working mother from Washington who recently spent six months battling lice on her 11-year-old daughter. “The lice would disappear from her head and then reappear,” Colburn recalls. “I went to the public library at the National Institutes of Health and read up everything on lice. I borrowed a magnifying glass that is used in the museum for conservation work so that I could check her head for lice. I tried every shampoo on the market. I bagged all her toys. I washed 20 loads of laundry every week. But they would just keep coming back.” Says Kramer, the medical entomologist: “It’s so frustrating for so many people. We can’t really recommend products that are 100% effective.”

As a result, parents have been turning to all sorts of bizarre alternatives, including eucalyptus and neem oils and chrysanthemum-flower extract, solutions that have been recommended on the Internet. Others have taken to smearing their children’s heads with mayonnaise, petroleum jelly or Crisco, then having the kids sleep in a shower cap. In July a 13-year-old girl in Lorimor, Iowa, died after her mother doused her head in gasoline and a pilot light on the family’s hot-water heater ignited the fumes. Last spring, a six-year-old Oklahoma girl stopped breathing temporarily after her mother’s boyfriend soaked her hair in Diazinon, an agricultural insecticide. “It’s a commentary on how bad the situation is,” says Kramer. “Physicians are running out of things to tell people to use.”

And what do the experts recommend? The key is removal of the nits, which are much harder to spot than the full-grown lice and which only lead to more of the insects if they are not painstakingly picked or combed out during thorough examinations of a child’s hair. Some kids may benefit from a number of over-the-counter products, but their efficacy varies from case to case. For nit and lice removal, several school systems are experimenting with a metal-toothed comb endorsed by the nonprofit National Pediculosis Association. Advice on insecticides and home remedies, as well as on the best methods for cleaning sheets, clothing and pillowcases, is reviewed in two new books, Wiping Out Head Lice by Nicholas Bakalar (Signet; $5.99) and The Lice-Buster Book: What to Do When Your Child Comes Home with Head Lice by Lennie Copeland (Warner Books; $8.99).

In the end, the worst pain inflicted by the louse may be psychological, the disgust and embarrassment of discovering that one’s head is an ecosystem for insects. “It is a very traumatic experience,” says Copeland, whose daughter suffered from head lice while attending an upscale girls’ school in San Francisco. “I think it goes back to some primitive reaction. We just go crazy with lice.”

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By Kevin Fedarko

With Reporting by Dan Cray/Los Angeles, Chandrani Ghosh and Wendy King/Washington and Andrea Sachs/New York

*The author cited above is not in any way affiliated with Rainforest Essentials. Their citation is offered solely for informational purposes and not to be construed as an endorsement of Lice Off!™ in particular or any of our products in general.